Demonstration of long-period-grating efficient couplings with an external medium of a refractive index higher than that of silica

Abstract

We discuss the behavior of the transmission spectra of a long-period grating (LPG) with an external medium of refractive index higher than that of silica. We studied the evolution of the features of LPG's surrounded by several liquid media for several kinds of fiber. The study demonstrated that the behavior depends strongly on the fiber type. Efficient couplings (efficiency greater than 50%) have been obtained with an external medium of a refractive index larger than that of silica. This result indicates that a LPG can operate with surrounding materials of a refractive index higher than that of silica, promising new applications for LPG's as active optical filters.

Engineering liquid crystals for optimal uses in optical communication systems

“…Experimental results with SmAs have shown tuning ranges of about 10 nm with good selectivity (v0.5 nm) [127]. Similar operations have been performed with a fibre as guiding medium surrounded by a nematic LC to provide a tuneable long period grating [13] or fibre tapers [128]. 7.6.2.…”

“…A large number of applications have been proposed in the telecommunication domain, including waveguides [12], LPG [13], switches [14], polarization shifters [15], polarization controller [16] and Fabry-Perot tuneable filters [17]). Some illustrations are given and discussed in § 7.…”

Thermal and Orientational 2D+1 Spatial Optical Solitons in Dye Doped Liquid Crystals

“…This setup is installed on a polarizing microscope in such way that the capillary axis lies parallel to the microscope stage. The observations are made by means of the microscope illumination light or by just collecting the light coming from the source beam that is scattered by the liquid crystal in the oy direction ( Figure 1b) [11]. We also set up a second microscope in the perpendicular direction (ox, Figure 1b) to spot the source beam properly and to observe the system from another point of view.…”

Mechanically induced long-period fiber grating in side-hole single-mode fiber for temperature and refractive sensing

“…The characteristics of sensors based on LPG have been widely investigated over the past decade [4][5][6][7]. The LPG has been conventionally fabricated in an optical fiber by inducing periodic modulation on the fiber's core refractive index with a period of several hundred micrometers.…”